/quote] Can only comment on the Unit Singles, the steel 69/70 tank has the cut outs under the tank for the twin carbs so is common to the twins and singles. On the singles the under tank front strap is plain (2 bends just to give some clearance) and only bolts to the tank and not the frame. On the singles the strap stops the 2 halves of the tank parting ways under vibration.
kommando.....Thank you for confirming that. I believe the 69'-70' tank used on the Shooting Stars (441) was larger than the the one on the '69 250 and was shared with some of the twins??? That is as much a question as a statement.
When I had my '67 VR glass tank copied (in steel) I had them add inserts for the strap.
This makes my third swap out from a fiberglass tank to steel. This particular tank is larger than the other's I have here. Different cap too. Using 69/70 SS tank rubbers the tank is as stable as any I've had before. I have had 3-4 different scalloped tanks on the shelf....not 100% sure what they came off of.
I'm just trying to wrap my head around why BSA used a different system for the scalloped tank on a twin......or was it just a holdover from the Lightening's tank design?
Top pressing is the same bottoms are different
One way it is no problem & the other way you need to put a right angle throttle cabe in because the tank fouls on the carb cables
From memory twin on single was the problem child